| Vol. 99(6) October 2004 |  |
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Life Tables and Reproductive Parameters of Lutzomyia spinicrassa (Diptera: Psychodidae) under Laboratory Conditions Vol. 99(6): 603-607, October 2004 Jesús Escovar, Felio J Bello/+, Alberto Morales, Ligia Moncada*, Estrella Cárdenas Laboratorio de Entomología, Biología Celular y Genética, Departamento de Ciencias Básicas, Universidad de La Salle, Bogotá DC, Colombia *Laboratorio de Parasitología, Facultad de Medicina, Universidad Nacional de Colombia, Bogotá DC, Colombia Lutzomyia spinicrassa is a vector of Leishmania braziliensis in Colombia. This sand fly has a broad geographical distribution in Colombia and Venezuela and it is found mainly in coffee plantations. Baseline biological growth data of L. spinicrassa were obtained under experimental laboratory conditions. The development time from egg to adult ranged from 59 to 121 days, with 12.74 weeks in average. Based on cohorts of 100 females, horizontal life table was constructed. The following predictive parameters were obtained: net rate of reproduction (8.4 females per cohort female), generation time (12.74 weeks), intrinsic rate of population increase (0.17), and finite rate of population increment (1.18). The reproductive value for each class age of the cohort females was calculated. Vertical life tables were elaborated and mortality was described for the generation obtained of the field cohort. In addition, for two successive generations, additive variance and heritability for fecundity were estimated. Key words: Lutzomyia spinicrassa - life cycle - reproduction - population - heritability
The sand fly Lutzomyia spinicrassa (Morales, Osorno-Mesa, Osorno & de Hoyos, 1969) belongs to the group verrucarum, series townsendi and it has a wide geographical distribution in Colombia and Venezuela, mainly in coffee plantations. In Colombia, this species is vector of Leishmania braziliensis (Young et al. 1987, WHO 1990) and has been found around plantations of coffee in several towns of Boyacá, Norte de Santander, and Sucre departments (Alexander et al. 2001, Bejarano et al. 2003). Maingon et al. (1994) founded high populations of L. spinicrassa in coffee plantations infected with two species of Leishmania: L. mexicana and L. braziliensis in the states of Trujillo, Mérida, and Táchira (Venezuela). It is an antropophilic species and their feeding activity carries out mainly in the twilight and night hours, during every month of the year. The adults rest during the day inside tree holes (Alexander et al. 1992). The sand fly demands care and special maintenance for the establishment of a colony in the laboratory. Killick-Kendrick et al. (1977) were successful for the first time on colonizing and reproducing L. longipalpis (Lutz & Neiva). Their work was the basis for the establishment in Colombia of colonies of other species of Lutzomyia, such as those achieved by the following authors: Morales et al. (1984) with L. walkeri, Neira et al. (1998) with L. torvida and L. longiflocosa, Montoya et al. (1998) with L. evansi, Ferro et al. (1998) and Cárdenas et al. (1999) with L. shannoni, Cabrera et al. (1999) with L. ovallesi and Cabrera and Ferro (2000) with three species of Lutzomyia of the group verrucarum. The reproductive cycles of arthropod vectors play a fundamental role in the epidemiology of the disease they transmit. Parameters affecting transmission of disease include fecundity rate, mortality rate, density, distribution by ages, migration rate, and genetic variation of the vector arthropods (Black & Moore 1996, Tabachnick & Black 1996). However, none of this information is available for L. spinicrassa. To better understand baseline parameters of the life cycle, growth under experimental conditions was monitored. Horizontal life table was constructed based on the developmental time of each instar in a cohort of 100 females. Additionally, predictive population para-meters were calculated. Stage specific mortality data were collected and for two successive generations, the additive variance and heritability of fecundity were estimated. ACKNOWLEDGMENTS To Dr María del Pilar Corena, Whitney Laboratory, University of Florida, for her valuable comments and for reading the original manuscript. To the anonymous reviewers whose suggestions greatly improved the manuscript presentation. To Gilberto Torres for the continuous maintenance of the laboratory sand flies colony. Fig. 1 | Fig. 2 | Table I | Table II | Table III
Financial support: Colciencias (grant 1243-05-12416), Universidad de La Salle, Bogotá Colombia +Corresponding author: Fax: +57-1-286.8391. E-mail: fbellog@atenea.lasalle.edu.co, fbello@urosario.edu.co Received 14 June 2004 Accepted 2 September 2004
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